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20th CONGRESS OF THE
PHYCOLOGICAL SOCIETY OF SOUTHERN AFRICA
28-30 January 2004
Magaliesburg Conference Centre
Hosted by the School of Animal, Plant & Environmental Sciences
University of the Witwatersrand
A P& E S
Organising Committee:
Stuart Sym (Convenor)
Claudio Marangoni (Administrator)
Shalini Dukhan
Acknowledgements:
National research Foundation for assistance with the guest speaker.
Imperial Car Rental for a complimentary vehicle.
South African Seaweeds Concessionaire Association (SASCA) for prizes.
University of the Witwatersrand for stationery.
PROGRAM
Wednesday 28 January 2004
Arrival of delegates at Magaliesburg Conference Centre
15h00
Registration
19h00
DINNER
Thursday 29 January 2004
09h00 - 09h10 Welcoming and Opening - Grant Pitcher
SESSION A - Invited Speaker - Chair: John Bolton
09h10 - 10h00 Millar, AJK - Phycological Forays _ the Good, the Bad, and the Algae
SESSION B - Oral presentations on Population Dynamics - Chair: Derek Du Preez
10h00 - 10h20 Pitcher, GC et al. - Satellite monitoring of the evolution of a coccolithophorid bloom in the
southern Benguela ecosystem.
10h20 - 10h40 Skinner, T et al. - Temporal and spatial variation in microphytobenthic biomass in relation to
changes in physico-chemical characteristics of a small temporarily open/closed estuary
in the Eastern Cape.
10h40 - 11h10 TEA
SESSION C - Oral presentations on Population Dynamics (cont.) - Chair: Grant Pitcher
11h10 - 11h30 Velikova, VN - The Black Sea phytoplankton seen through an “environmental window”.
11h30 - 11h50 Du Preez, DR - Why don’t bacterial numbers increase in surf diatom patches?
11h50 - 12h10 Gama, PT & Adams, JB - Seasonal distributions in phytoplankton size fraction by mass
associated with changes in physical and chemical variables in a temporarily open/closed
estuary in the Eastern Cape, South Africa.
12h10 - 12h30 Clark, BJ et al. - Microalgae as indicators of coastal pollution.
12h30 - 12h50 Difford, M & Campbell EE - On curing macroalgae: The effect of salt on salt works.
12h50 - 14h00 LUNCH
SESSION D - Oral presentations on Distribution - Chair: Eileen Cambell
14h00 - 14h20 Anderson, RJ et al. - Seaweed endemism in the proposed Pondoland marine protected area.
14h20 - 14h40 Bolton, JJ et al. - Seaweed diversity in sub-Saharan Africa: the known and the unknown.
14h40 - 15h00 Maneveldt, GW & Bassier, A - The role of selected herbivores in the control of intertidal
seaweed diversity.
15h00 - 15h20 Tronchin, EM et al. - The diversity and distribution of Ptilophora (Gelidiaceae, Rhodophyta)
including two new species from Kwazulu-Natal.
15h20 - 15h40 Snow, GC & Adams, JB - Physico_ chemical factors determining benthic microalgal distribution
in open South African estuaries.
15h40 - 16h15 TEA
16h15
PSSA Annual General Meeting
19h00
DINNER
Friday 30 January 2004
SESSION E - Oral presentations on Biodiversity - Chair: Claudio Marangoni
09h00 - 09h20 Mason, RM & Sym, SD - An unusual gymnodinioid dinoflagellate (Dinophyceae) from the
waters off the South Western Cape.
09h20 - 09h40 Sym, SD et al. - On the identity of a bloom-forming Tetraselmis from Saldanha Bay.
09h40 - 10h00 Campbell, EE - The surf diatoms of Australasia.
10h00 - 10h20 Dukhan, S et al. - Further studies on the marine dinoflagellate Lepidodinium viride.
10h20 - 10h40 Griffin, NJ et al. - Cryptic biodiversity in Porphyra in southern Africa.
10h40 - 11h00 Millar, AJK & Bolton, JJ - Sharing Marine Algae - Australia and South Africa.
11h00 - 11h30 TEA
SESSION F - Poster presentations - Chair: Wendy Stirk
1.
Kirton, A et al. - Coccolith production over time in Pleurochrysis carterae under continuous light and
dark conditions.
2.
Buchanan, S et al. - Testing for exotoxin expression in Prymnesium nemamethecum.
3.
Evans, AG et al. - Subtidal seaweed communities of Kwazulu-Natal: Their diversity and biogeography.
4.
Campbell, EE & Smith AC - Dinoflagellates and diatoms indicate different water quality conditions in
Algoa Bay.
5.
Todkill, WB et al. - A sandy beach ecosystem health index and expert system for beach management
in the Eastern Cape.
6.
Difford, M & Campbell EE - On curing macroalgae: Looking for a less-nutrient-rich water source in the
Swartkops estuary.
7.
Salum, DM - Effects of north east (NE) and south east (SE) monsoons on growth of Kappaphycus
alvarezii growing in Zanzibar.
8.
Steyn, PP & Du Preez, DR - Cultivating Gelidium pristoides in a spray cultivation system.
13h00 - 14h00 LUNCH
SESSION G - Oral presentations on Applications - Chair: Robert Anderson
14h00 -14h20 Naidoo, K - Testing the suitability of local seaweeds as feed for abalone.
14h20 - 14h40 Smit, A J - The current state of seaweed natural products (bioactive
compounds) in drug discovery.
14h40 - 15h00 Rand, AM et al. - Introducing a spatial geographic information system (GIS) into
kelp management in South Africa.
15h00 - 15h30 TEA
SESSION H - Oral presentations on Applications (cont.) - Chair: Gavin Maneveldt
15h30 - 15h50 Robertson-Andersson, DV et al. - A preliminary investigation into modelling an
integrated seaweed (Ulva lactuca) and Abalone (Haliotis midae) system.
15h50 - 16h10 Rothman, MD et al. - The effects of kelp (Ecklonia maxima) harvesting on kelp
population structure and kelp recruitment.
16h10 - 16h30 Stirk, WA et al. - Potential benefits of using microalgae (Chlorophyta) as soil
additives for agricultural application.
16h45
8th International Phycological Congress - Local Organising Committee
19h00
DINNER & Prize Giving
Saturday 31 January 2004
Delegates depart after breakfast.
ABSTRACTS
SEAWEED ENDEMISM IN THE PROPOSED PONDOLAND MARINE PROTECTED AREA (oral)
1
Robert J. Anderson1, J. J. Bolton2, H. Stegenga3 and O. DeClerck4
Seaweed Unit, Marine and Coastal Management, Pvt Bag X2, Roggebaaai, 8012
2
Botany Department, University of Cape Town
3
Research Group Phycology, Ghent University, Belgium
4
National Herbarium Nederland, The Netherlands
[email protected]
Until recently, the seaweed flora of the east coast of South Africa was relatively poorly known. Recently we
have made extensive collections in the Eastern Cape (Netherlands/SA project) and in Kwazulu_Natal
(SA/Flanders project). From an analysis of our distribution records in 50_km blocks around the entire SA
coastline of 3000 km, we have identified two areas with exceptionally high numbers of "endemics with very
restricted distributions" (species recorded from ranges of 50_250 km). The two areas are the Cape Peninsula
(not dealt with here) and Pondoland (in our analysis a 150_km stretch from just south of Port St Johns to just
north of Port Edward). About 10 species of seaweeds (representing 35% of SA "restricted endemics" and
including two undescribed genera) appear to be endemic to this short Pondoland region. Recent collections
from this area (by ORI, Durban) confirm the unique character of the subtidal element of the seaweed flora. We
discuss examples of these range_restricted species. These results, based on one of the few components of
the marine biota that has been intensively sampled (seaweeds), further illustrate the exceptional biological
value of the Pondoland coast and should aid efforts to conserve this area.
SEAWEED DIVERSITY IN SUB_SAHARAN AFRICA: THE KNOWN AND THE UNKNOWN (oral)
John J Bolton1, O. De Clerck2 and D. M. John3
1
Botany Department, University of Cape Town
2
Research Group Phycology, Ghent University, Belgium
3
Department of Botany, The Natural History Museum, London
[email protected]
This paper summarises a contribution put together for a workshop on 'Marine Biodiversity in Sub_Saharan
Africa', which took place in September 2003, under the auspices of the 'Census of Marine Life'. Despite some
gaps, the seaweed information was shown to be one of the most complete datasets on inshore marine
biodiversity in the region. Recent advances, including web_based systems, are ensuring that the information
which is available can be more easily accessed. In Tropical West Africa only a small number of countries are
well_collected. South Africa and Namibia have quite well documented seaweed floras, although detailed
collections, especially in the subtidal, or detailed studies of taxa, particularly using molecular methods,
anywhere in the region are likely to bring up new species or records. South Africa has a very rich seaweed
flora (ca. 850 species), due to its borders encompassing a portion of three of the four major biogeographic
regions in sub_Saharan Africa. In Tropical East Africa the seaweed floras of Somalia and Mozambique are not
well known. Figures for reasonably well_studied countries in Tropical East Africa are more than 400 species,
whereas much of Tropical West Africa has lower numbers (e.g. 200 species in well_studied Ghana). Factors
which may account for these major differences in diversity patterns are discussed. Training workshops in
Africa are necessary to recruit a body of local scientists able to identify and work with seaweeds, and to make
the wealth of information in the international literature available to African marine scientists. A network of
national herbaria should contain a collection of correctly identified seaweed species.
TESTING FOR EXO_TOXIN EXPRESSION IN Prymnesium nemamethecum (poster)
Sean K. Buchanan, R. O’Shaughnessy and N. Tye
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
[email protected]
Prymnesium nemamethecum is a sand_dwelling marine species that resembles other species of the genus in
size, organelle arrangement and swimming behaviour. Several species of Prymnesium have been known to
produce exudates that are ichthyotoxic, and have been observed in toxic algal blooms in Europe. The
potential of P. nemamethecum to be toxic needs to be tested. To this end, a unialgal isolate was cultured
under 5 different nutrient regimes, consisting of varying concentrations of PES, and their ambient medium
tested for ichthyotoxicity using Artemia shrimp as the bioassay organism. All culturing was achieved under
uniform light and temperature conditions. Three replicates of each treatment were tested for toxicity. No
significant difference in mortality was found across the treatments. The results indicate that under these
conditions P. nemamethecum does not express an exo_toxin. Further studies are needed to elucidate whether
this is true of the species under all conditions or whether it is an artefact of the culture conditions.
THE SURF DIATOMS OF AUSTRALASIA (oral)
Eileen E. Campbell
Botany Department, University of Port Elizabeth
[email protected]
Six diatom species are known to form semi_permanent brown discoloration in surf_zones. Generally, only one
species will form these brown patches at a given time, and generally only one or two species will dominate at a
sandy beach. This rule applies to all beaches studied with the exception of a beach on the north island of New
Zealand. Five of the six species where recorded at this beach in a single patch. Diel and long_term dynamics
of this phenomenon were investigated. Some species are semi_permanent features of the beaches where
they are recorded (e.g. Attheya armatum), others may be episodic (e.g. Asterionellopsis glacialis), while others
appear or disappear depending on the surf conditions (e.g. Anaulus australis). Finding all these species at one
beach offers a unique opportunity to compare their different dynamics.
DINOFLAGELLATES AND DIATOMS INDICATE DIFFERENT WATER QUALITY CONDITIONS IN ALGOA
BAY (poster)
E. E. Campbell and Andy C. Smith
Botany Department, University of Port Elizabeth
[email protected]
Phytoplankton samples were assessed for abundance of dinoflagellates and diatoms over a diverse grid of
stations in Algoa Bay. The grid enclosed three islands _ their presence creating pools of nutrient_rich water in
an oligotrophic system. Dinoflagellate and diatom species composition was assessed using multivariate
analysis and spatial analysis using Kriging algorithms. The different groups of microalgae dominated in
different water conditions. While this phenomenon is known for large_scale nutrient conditions, it is now shown
to apply on a smaller scale. Microalgal assemblages were found to be associated with island_enriched waters.
MICROALGAE AS INDICATORS OF COASTAL POLLUTION (oral)
Belinda J. Clark, E. E. Campbell and D. R. Du Preez
Botany Department, University of Port Elizabeth
[email protected]
Internationally, most countries report that the major threat to their coastal environment is nutrient enrichment,
arising mostly from stormwater runoff or leaks in septic tanks and run_off from agricultural lands. Along the
South African coastline, there are 63 waste discharge pipelines and numerous storm water pipes, therefore
the potential for nutrient enrichment and associated problems is high if discharges from these outlets are not
monitored and properly managed. The White Paper recognises our coast as being a national asset belonging
to all the people of South Africa. It recognises the coast as being a place of value, opportunity and potential,
whose products account for approximately 35% of our national Gross Domestic Product with enormous future
development potential. Therefore, we need to manage our coast wisely, which includes maintaining the
diversity, health, and productivity of coastal ecosystems. Proactive monitoring efforts can identify problem
areas, allowing steps to be taken prior to the collapse of a system.
In order to characterise anthropogenic impacts on ecosystems more accurately, environmental monitoring has
moved in the direction of using measures of ecological condition rather than chemical indicators. Historically,
algae have been an important part of biological monitoring programs, providing unique information because of
their nutritional needs and position at the base of the food web. Algae respond rapidly to a wide range of
pollutants and serve as early warning signals of deteriorating environmental conditions.
The aim of this study was to assess pollution levels (in terms of nutrient enrichment) and associated microalgal
species composition in surf_zones of sandy beaches along the South African coastline, with the hope that
certain species would be highlighted as indicators of environmental condition. Nine beaches were selected for
study and were sampled four times. Surf_zone water samples collected were analysed for inorganic nutrients;
and pH, temperature and salinity levels. Surf_zone widths and wave heights were estimated, and microalgal
species present were identified and counted.
The following microalgal species were indicative of particular environmental variables on a number of beaches
on more than one occasion:
•
•
•
Ammonium: Scrippsiella trochoidea, Prorocentrum micans, Dinophysis ovum
Nitrate and Phosphate: Chaetoceros species in general, Pleurosigma normanii, Rhizosolenia
styliformis, a silicoflagellate species, Bacteriastrum delicatulum, Aulacodiscus johnsonnii
Temperature: Protoperidinium diabolum, Chaetoceros curvisetus, Ditylum brightwellii
ON CURING MACROALGAE: THE EFFECT OF SALT ON SALTWORKS (oral)
Mark Difford and E. E. Campbell
Botany Department, University of Port Elizabeth
[email protected]
Swartkops Sea Salt, on the outskirts of Port Elizabeth, is the largest individual producer of sea salt in South
Africa. High nutrient levels in the brine_source, coupled with low salinity in the early and middle ponds of the
system, have led in recent years to an increasing number of macroalgal blooms.
The breakdown products of these blooms, in the form of blackened detrital particles, enter the crystallisers,
where they interfere with crystallization and deleteriously affect the quality of the salt.
During the past year a number of remedial measures to alleviate this problem have been implemented. These
have included (1) decreasing pond depth and (2) increasing the salinity of the middle pond of the system. The
effects of these changes are described.
ON CURING MACROALGAE: LOOKING FOR A LESS NUTRIENT_RICH WATER SOURCE IN THE
SWARTKOPS ESTUARY (poster)
Mark Difford and E. E. Campbell
Botany Department, University of Port Elizabeth
[email protected]
Physico_chemical factors in the Swartkops estuary were assayed on a weekly basis for seven weeks, during
six hours of the tidal cycle. Several sites (prospective sites for a new pump_house), including that of the
current pump_house, were studied. The purpose of the survey was to rank the sites in order of brine_quality,
suitable for use in a solar saltworks. Nutrient concentration and salinity were therefore chosen as the
appropriate ranking_factors. At all sites, tidal factors strongly influenced brine_quality. Site_distance from the
mouth is therefore critical, as, from a remedial standpoint, is the pumping regime of the salina. With the
exception of a proposed site near the mouth, the site of the present pump_house was found to be the best of
the sites examined.
FURTHER STUDIES ON THE MARINE DINOFLAGELLATE Lepidodinium viride (oral)
Shalini Dukhan, S. D. Sym and R. N. Pienaar
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
[email protected]
Lepidodinium viride has a bright green pigmentation due to the presence of the prasinophyte endosymbiont
harboured within the dinoflagellate. However, colourless cells are encountered in culture. It was initially
thought that the presence of colourless cells was due to an uneven division of the enodsymbiont, which
prompted investigations on endosymbiont division. Preliminary light microscope investigations revealed that
the study of the division of the endosymbiont would be complex as the endosymbiont is already highly
dissected and it would therefore be difficult to determine when cytokinesis of the endosymbiont begins or
ends. There was no evidence of an unequal division of the endosymbiont between daughter cells. Only
pigmented daughter cells were ever observed to develop from a pigmented parent cell. It is thought that
colourless cells develop through an ageing process, which results in the degradation of the chloroplasts into
accumulation bodies. Eventually even these accumulation bodies are broken down by the cell, thus rendering
the cell colourless.
The athecate gymnodinioids were traditionally divided into three genera, Amphidinium, Gyrodinium and
Gymnodinium. However, more recent DNA analysis has shown that this system is too simple and more
genera (e.g. Karenia) are required. According to this system, Lepidodinium viride has now been reclassified
into Gymnodinium based on light and electron microscopic features (e.g. cytoskeletal studies, division, nuclear
envelope structure, cingular displacement, the position of the apical groove). Observations to confirm the
presence of these distinguishing features in Lepidodinium viride will be presented.
WHY DON'T BACTERIAL NUMBERS INCREASE IN SURF_DIATOM PATCHES? (oral)
Derek du Preez
Botany department, University of Port Elizabeth
[email protected]
Surf_diatom accumulations, or patches, in surf_zones are the result of the accumulation of the cells of certain
diatom species (six the world over) to concentrations often in excess of 1 million cells per millilitre. In South
Africa the species most commonly responsible for the patches is Anaulus australis. In South America it is
Asterionellopsis glacialis. In accumulations of both species it has been noted that the bacterial numbers are
not significantly higher than they are in the surrounding water, where diatom numbers are very much lower.
This is surprising in light of the fact that the cells exude into the water, in the form of various organic
compounds, about half of the carbon that they fix during photosynthesis. This high concentration of organic
compounds should enable bacteria to grow very well within the diatom accumulations and yet their numbers
do not increase.
Various reasons for the lack of high bacterial numbers in the patches have been put forward. The most
plausible of these is that anti_bacterial compounds produced by the diatoms inhibit the bacteria. In this paper I
suggest another possibility and that is that the bacterial numbers do not increase in the patches simply
because the bacteria, like other microalgal species that occur in surf_zones, do not have the mechanism that
allows them to accumulate in the same way as the specialist surf_zone diatoms do.
SUBTIDAL SEAWEED COMMUNITIES OF KWAZULU_NATAL: THEIR DIVERSITY AND BIOGEOGRAPHY
(poster)
Adrian Evans1, R. J. Anderson2 & J. J. Bolton1
1
Botany Department, University of Cape Town
2
Seaweed Unit, Marine & Coastal Management
[email protected]
Despite the important taxonomic contributions of previous workers, most recently R. E. Norris, the composition
and structure of subtidal seaweed communities in KwaZulu-Natal [KZN] has been little studied. A collaboration
between phycologists from the University of Cape Town, Marine & Coastal Management and University of
Gent has identified the Cape St Lucia area as the junction between the tropical Indo_West Pacific flora and a
warm_temperate South Coast flora, based on intertidal collections. This study aims to characterise the main
subtidal seaweed communities on both sides of this junction in order to test whether they show a similar
biogeographical pattern, and to provide the first description of these communities. All seaweeds were scraped
off the substrate within a series of 25 x 25cm quadrats at a range of depths from 0.5 _ 20m at 9 sites between
Rocktail Bay in the north and Aliwal Shoal in the south, and formalin preserved samples identified and
weighed. A series of five continuous temperature recorders has been deployed over the study range. Species
distributions and biomass data will be analysed and related to environmental measurements using ordination
methods. Provisional results show an increase in the number of species from south to north but a decrease in
the biomass and size of the dominant species. Like the intertidal species, the subtidal seaweeds appear show
a biogreographic disjunction around Cape St Lucia. This is where the narrow continental shelf widens in the
Natal Bight, the warm Agulhas Current moves further offshore, and the water over the bight is cooler and more
turbid.
SEASONAL DISTRIBUTIONS IN PHYTOPLANKTON SIZE FRACTION BIOMASS ASSOCIATED WITH
CHANGES IN PHYSICAL AND CHEMICAL VARIABLES IN A TEMPORARILY OPEN/CLOSED ESTUARY
IN THE EASTERN CAPE, SOUTH AFRICA (oral)
Phumelele T. Gama and J. B. Adams
Department of Botany, University of Port Elizabeth
[email protected]
Monthly sampling of size_fractionated phytoplankton was carried out at five stations along the length of the
Van Stadens estuary, located 30km west of Port Elizabeth, from May 2001 to May 2002. Sampling included
physico_chemical parameters, nutrients, and size_fractionated phytoplankton biomass. Biomass was
measured in terms of chlorophyll a for three size fractions, pico_ (<3.0m), nano_ (3.0_20m) and
microphytoplankton (>20m). The estuary mouth was breached approximately 40% of the time during that
period and was usually associated with rainfall events. Nutrient concentrations showed a maxima during
periods of increased river inflow exhibiting higher levels in the upper reaches. During the closed mouth period
nutrient levels were always low and displayed no spatial variation. River inflow rapidly established freshwater
conditions throughout the estuary lasting about 4_5 days and was subsequently followed by a strong
horizontal and vertical salinity gradient as out flowing freshwater interacted with inflowing marine water. These
conditions were associated with an increase in picophytoplankton biomass that contributed over 60% to total
phytoplankton biomass, particularly in the surface waters of the lower reaches. By late spring, as
temperatures began to rise, the microphytoplankton biomass fraction constituted 75% of the total
phytoplankton biomass throughout the vertical and horizontal water column of the estuary. This pattern
remained the same through the summer and autumn seasons. Rainfall events ceased during summer and
autumn periods and the estuary mouth remained closed. Nutrient input from river inflow appears to initially
stimulate small_sized phytoplankton however, over extended periods are replaced by larger_sized forms.
These phytoplankton patterns may have important effect for food web dynamics in that microplankton grazer
populations can rapidly exploit picophytoplankton over short periods (i.e. season) thus channelling energy to
small_sized planktivores (e.g. fish larvae). Furthermore, as microphytoplankton replace picophytoplankton
perhaps a supply of energy resource is ensured for macrograzers that in turn support young_of_the_year fish.
CRYPTIC BIODIVERSITY IN Porphyra FROM SOUTHERN AFRICA (oral)
Neil J. Griffin1, W. A. Jones2, D. T. Jones2, W. A. Nelson3, T. J. Farr3 and J. E. Broom2
1
Department of Botany, University of Cape Town
2
Department of Biochemistry, University of Otago, New Zealand
3
National Institute for Water and Atmospheric Research, Wellington, New Zealand
[email protected]
Porphyra, an economically important genus, currently contains more than 130 species. Recent work using
genetic data along with traditional morphological characters has revealed a level of variation in the genus that
was previously not suspected or detected.
Porphyra from Southern Africa was first described, as P. capensis and P. augustinae, by Kützing in 1843. The
two taxa were soon synonymised by J. Agardh. Isaac and Graves later maintained this view, and further held
that P. capensis was a morphologically and ecologically plastic taxon to which all South African Porphyra
records that they had examined could be assigned. In 1997, Stegenga, Bolton and Anderson described one
new Southern African Porphyra species, and recorded two new species. Griffin, Bolton and Anderson later
described another new species.
This paper presents an estimate of biodiversity in summer populations of South African Porphyra, based on
analysis of 18S rDNA. A high level of genetic diversity in Porphyra was detected, and 10-14 species seem to
be present in the sample.
COCCOLITH PRODUCTION OVER TIME IN Pleurochrysis carterae UNDER CONTINUOUS LIGHT AND
DARK CONDITIONS (poster)
Alecia Kirton, K. Crossley, H. P. Meintjies, H. P. and C. Rossin
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
[email protected]
Pleurochrysis carterae, a member of the Prymnesiophyceae, is referred to as a coccolithophorid because it
produces calcified scales called coccoliths, which collectively form a coccosphere around the cell. Two
opposing theories exist to explain the driving force behind coccolith production: either the production of
coccoliths is simply induced by the incompleteness of the coccosphere or by the levels of calcium in an
internal pool which are maintained by photosynthesis. The aim of this study was to test these hypotheses by
investigating the effect of light on coccolith production in this alga. This was undertaken by growing the alga
either in constant light or in constant darkness over a period, after first removing all coccoliths. The rate of
recovery of the coccolith covering was followed under each condition. After 1½ hours, there was a significant
difference between the two treatments, with coccolith production continuing in cultures grown under
continuous light, but tapering off in cultures left in the dark. It was concluded that light was critical for coccolith
production in this alga.
THE ROLE OF SELECTED HERBIVORES IN THE CONTROL OF INTERTIDAL SEAWEED DIVERSITY
(oral)
Gavin W. Maneveldt & A. Bassier
Dept. of Biodiversity and Conservation Biology, University of the Western Cape
[email protected]
The role of herbivores in the control of seaweed distribution patterns was observed within the intertidal zone at
Kalk Bay (False Bay), South Africa. The intertidal of Kalk Bay has a typical south coast zonation pattern with a
band of seaweed (mid_eulittoral zone) sandwiched between two herbivore_dominated zones. Copper_based
antifouling plots were established, within both a Patella oculus and a Siphonaria capensis dominated upper
eulittoral zone, to determine to effects that herbivores have on the distribution of seaweed within the upper
intertidal zone. Seaweed colonized the P. oculus and the S. capensis dominated zones within 1_2months and
3_4months respectively. This is overwhelming support for the biological control of the upper limits of algal
distribution. Furthermore, there is no difference in the heights of either the P. oculus or S. capensis dominated
zones. The S. capensis zone, however, has a naturally high cover of the encrusting, fleshy red seaweed,
Hildenbrandia lecanellierii. Preliminary data seems to suggest that the delayed establishment of seaweed
within the S. capensis dominated upper eulittoral zone could be a function of the presence of H. lecanellierii.
Here we present data and some anecdotal evidence in support of the biological control of intertidal seaweed
distribution by both herbivores and encrusting fleshy seaweeds.
AN UNUSUAL GYMNODINIOID DINOFLAGELLATE (DINOPHYCEAE) FROM THE WATERS OFF THE
SOUTH WESTERN CAPE (oral)
Richard M. Mason and S. D. Sym
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
[email protected]
An unusual bloom_forming gymnodinioid (naked dinoflagellate) was isolated from the waters off Lambert’s Bay
in 2002. This species has been reported as Gyrodinium zeta based on evidence at the light microscope level.
However the cingulum displacement and the absence of an elliptical apical groove do not support its inclusion
in the genus Gyrodinium. The morphology and ultra_structure most closely resembles those of Gymnodinium
natalense, a tidal pool dinoflagellate discovered from the KwaZulu-Natal coast. However the size, differences
in nuclear membrane and habitat between the two organisms suggests that this is a new, but closely related
species.
This organism has a unique eyespot containing highly distinctive crystalline structures. This feature is shared
by other four gymnodinioids: G. natalense, G. linuchiae, Amphidinium lacustre and Polarella antartica. The
phylogeny of the gymnodinioids is poorly understood and so the eyespot may represent a useful feature in
identification. Preliminary DNA analysis supports this because these species form a natural clade. This
feature as well as other elements of the ultra_structure will be presented.
PHYCOLOGICAL FORAYS _ THE GOOD, THE BAD, AND THE ALGAE (invited)
Alan J.K. Millar
National Herbarium of New South Wales, Royal Botanic Gardens Sydney, Australia
[email protected]
Australian phycology dates back to the first European settlers in the late 1700s and early 1800s when even the
Governors of the new colony collected seaweeds and sent them back to Europe. When the Irish phycologist
William Harvey arrived in Australia in 1854, a new and long standing interest in Australian phycology started,
ultimately showing the continent to host one of the richest marine floras of the world. Harvey collected 20,000
specimens from southern Australia in 6 months and many of these are housed at the Royal Botanic Gardens
in Sydney. We will revisit many of Harvey's collecting sites (Western Australia, South Australia, Victoria, and
New South Wales) and look at the marine algae that occur there now to see what changes if any have
occurred in the last 150 years.
SHARING MARINE ALGAE _ AUSTRALIA AND SOUTH AFRICA (oral)
Alan J. K. Millar 1 & J. J. Bolton 2
National Herbarium of New South Wales, Royal Botanic Gardens Sydney, Australia
Botany Department, University of Cape Town
[email protected]
Over the past several decades (at least since the 1960s), there has been a known similarity between the
marine algal floras of southern and Western Australia and the southern African coasts. These species consist
of a mixture of generally widespread species from other Indo_Pacific regions, and those that appear to be
restricted just to Western Australia and South Africa. Over the last few years, we have discovered several
species along the Kwazulu_Natal coast that were thought to be endemic to east Australia, in particular the
coast of New South Wales. These species will be illustrated and discussed from a morphological perspective,
and discussed in the context of Hommersand's dispersal model for the origins of the South African seaweed
flora.
TESTING THE SUITABILITY OF LOCAL SEAWEEDS AS FEED FOR ABALONE (oral)
1
Krishni Naidoo 1, G. Maneveldt 1, K. Ruck 2, J. Bolton 3
Department of Biodiversity and Conservation Biology, University of the Western Cape
2
Jacobsbaai Sea Products
3
Botany Department, University of Cape Town
[email protected]
This project is investigating the growth of the South African abalone, Haliotis midae, in an Integrated
Mariculture System. There are 6 abalone species in South Africa of which only the perlemoen, Haliotis midae,
is presently fished commercially. Good growth rates are crucial to the success of abalone mariculture. Growth
rates of juvenile abalone were measured on the Jacobsbaai Sea Products farm. Growth was monitored over 2
periods of 9 months and 7 months and consisted of 9 and 13 treatments respectively, with 4 replicates (with
1000 individuals per treatment). The first feed treatments (presented here) were: fresh kelp blades (control);
abfeed (artificial feed as a control); kelp + abfeed; dried kelp pellets, dried blades of kelp washed up on the
shore, stipes of kelp, kelp with the epiphyte; mixed diet (seaweeds, Gracilaria sp., Ulva sp. and kelp) and a
rotational diet (where the abalone were fed 1 of the 9 treatments for the first week and then kelp for the next 3
weeks). Measurements of shell length (mm) and weight (g) were taken monthly and results of the initial study
suggest that the mixed diet (Kelp, Ulva sp.and Gracilaria sp.) produces the best growth rates. Abalone are
sold by weight, so better growth rates in weight as opposed to length is preferred. The mixed diet produces
higher growth rates because of the increased nitrogen content that is a direct result of the integrated system.
Seaweeds, in particular Ulva sp. and Gracilaria sp. are grown in abalone and turbot effluent. Farm grown Ulva
sp. have been shown to have 40% more nitrogen , compared to wild Ulva sp. The abalone grown on the mixed
seaweed treatments grow faster and are larger as compared to conventionally grown abalone. The growth
period is cut down, that is, bigger abalone can be grown in a shorter time period. Economic data shows a huge
saving with respect to money, time, energy and effort.
SATELLITE MONITORING OF THE EVOLUTION OF A COCCOLITHOPHORID BLOOM IN THE
SOUTHERN BENGUELA ECOSYSTEM (oral)
Grant C. Pitcher1, S. J. Weeks2 and S. Bernard3
1
Marine and Coastal Management, Cape Town
2
OceanSpace CC, Department of Oceanography, University of Cape Town
3
Department of Oceanography, University of Cape Town
[email protected]
Coccolithophorids are globally cosmopolitan and known to form near mono_specific blooms that can extend
over large areas of the ocean surface. These blooms provide a milky turquoise in colour to the ocean, owing to
the scattering properties of the coccoliths. Consequently these blooms differ optically from other blooms of
non_calcifying marine phytoplankton owing to their high effective refractive index and typically small size. An
increased backscattering to absorption ratio induced by the presence of coccoliths is responsible for the
increased reflectance values associated with these blooms allowing them to be easily distinguished from
satellite. The evolution of such blooms can therefore be analysed using satellite_derived pseudo_true colour
imagery as an alternative to the traditional phytoplankton biomass proxy of chlorophyll a concentration. Here
we document the evolution of a coccolithophore bloom in the southern Benguela along the west coast of South
Africa during the autumn of 2003 by means of a sequence of satellite images from the period 26 March to 5
May 2003. Dominated by Syrachosphaera pulchra, the bloom was confined to the region between the
Namaqua and Cape Columbine upwelling cells, where a broadening of the shelf favours stratification of the
water column, conducive to the development of flagellate dominated blooms. The bloom was first observed to
the north of St Helena Bay following a period of moderate upwelling. The bloom was associated with warm
water (16oC) on the seaward edge of the upwelling front demarcating a narrow band of upwelling inshore.
Under diminished upwelling activity and increased thermal stratification the bloom intensified and was
advected into St Helena Bay. Termination of the bloom was associated with quiescent conditions and
extensive warming of St Helena Bay, 41 days after the bloom was first observed.
INTRODUCING A SPATIAL GEOGRAPHIC INFORMATION SYSTEM (GIS) INTO KELP MANAGEMENT IN
SOUTH AFRICA (oral)
Andrew M. Rand1, J. J. Bolton1, R. Anderson2, and S. Butcher3
1
Botany Department, University of Cape Town
2
Seaweed Unit, Marine and Coastal Management
3
Environmental and Geographical Science Department, University of Cape Town
[email protected]
This research aims to improve the management of kelp beds along the South African coastline. This study is
using existing infrared aerial imagery of most of the west coast, together with new surveys (using Global
Positioning Systems), ancillary biomass data, and information on infrastructure, into a Geographical
Information System (GIS). For the first time, this will integrate all available data to improve the management
and allocation of South African kelp resources.
A PRELIMINARY INVESTIGATION INTO MODELLING AN INTEGRATED SEAWEED (Ulva lactuca) &
ABALONE (Haliotis midae) SYSTEM (oral)
Deborah V. Robertson_Andersson1, A. Govender 2, T. Probyn3, C. Halling4, M. Troell5, J. Bolton1
& R. Anderson6
1
Botany Department, University of Cape Town
2
Zoology Department, University of Cape Town
3
Mariculture Unit, Marine and Coastal Management
4
Department of Systems Ecology, Stockholm University, Sweden
5
The Beijer Institute, The Royal Swedish Academy of Science, Stockholm, Sweden
6
Seaweed Unit, Marine and Coastal Management
[email protected]
Previous studies in Israel and elsewhere have shown that Ulva lactuca is capable of removing significant
amounts of nutrients (60 _ 85%) from aquaculture effluents. These systems are built on vertical integration
(i.e. not closed systems) and models of such systems use whole farm approaches. This study aims to
investigate and model the physico_chemical dynamics of a farm section. A single tank containing a single size
class of abalone was integrated with seaweed in 5 m2 tumble culture tanks stocked at 3 kg.m-2. Three
seaweed tanks were integrated with one abalone tank, containing approximately 13 200 abalone with an
average weight of 15g. The system was replicated three times. 9 different abalone control tanks were also
set up, each being fed different diets (ABFEED ®, mixed seaweed diet and a kelp only diet). This was done in
order to investigate different diets influence on abalone excretion. Seasonal changes in growth, nutrient
concentrations, oxygen and pH are being monitored in both the abalone and seaweed tanks. Parasitic loading
of the abalone fed the different diets, as well as in the integrated abalone_seaweed system are also being
monitored. Preliminary evidence suggests that diet has a huge effect on both excretion rates and
physiochemical variables, with ABFEED ® having the highest excretion concentrations. In attempting to
model the system, mass balance equations are being used. The data clearly shows two major challenges
exist in a closed abalone seaweed system. The first is the diel relationship between oxygen and pH in the
seaweed systems. As the seaweeds start to respire at night, abalone experience an increase in oxygen
demand, due to night time feeding activity and excretion in the abalone systems, which has implications for the
management of ammonia. The second complication is that seaweed uptake decreases at night when abalone
excretion reaches a maximum.
THE EFFECTS OF KELP (Ecklonia maxima) HARVESTING ON KELP POPULATION STRUCTURE AND
KELP RECRUITMENT (oral)
Mark D. Rothman1,2, R. J. Anderson1, J. J. Bolton2, A. J. Smit2, C. J. T. Boothroyd1 and F. A. Kemp1
1
Seaweed Unit, Marine and Coastal Management
2
Botany Department, University of Cape Town.
[email protected]
The recent increase in abalone farms has drastically increased the demand for harvested kelp (Ecklonia
maxima) in the Western Cape. We present some preliminary results of a study on the kelp population
demography associated with different harvesting strategies conducted along the Cape Peninsula. The two
types of harvesting (cutting fronds only or removing whole kelp heads) do not appear to affect growth rates
and establishment of juvenile plants in the relatively open kelp beds under investigation. This suggests that the
population dynamics of the beds are not determined by light penetration. An interesting feature that emerged
from the data is the decrease in growth rate during long periods of calm, warm sea conditions, when nutrient
are also probably low. The preliminary conclusion from the first year of the study is that for beds in which light
is assumed to be a non_limiting factor, the two harvesting methods studied do not affect the establishment of
new plants. In the longer term this could be expected to result in similar biomass/abundance of adult plants,
irrespective of harvesting strategy. Uncontrollable environmental conditions such as water
temperature/nutrients may more directly affect kelp population dynamics than the types of harvesting tested
here.
EFFECTS OF NORTHEAST (NE) AND SOUTHEAST (SE) MONSOONS ON GROWTH OF Kappapyhcus
alvarezii GROWING IN ZANZIBAR (poster)
Dotto M. Salum
Institute of Marine Sciences, Zanzibar, Tanzania
[email protected] (or) [email protected]
Seaweed (Kappaphycus alvarezii (Doty) Doty, and K. striatum Schmitz) farming has played an important great
role in the Zanzibar Island's domestic economy by providing employment to coastal villagers, mostly women.
Despite the success, direction of monsoon trade winds had great effects in seaweed farming. The aim of this
study, was to describe the role of Northeast and Southeast monsoons in the growth of Kappaphycus alvarezii,
with regards namely the effects of water temperature, light intensity, and salinity. The growth rate of green and
red strains of Kappaphycus alvarezii (Doty) was investigated using an off_bottom monoline cultivation system
in Zanzibar (Jambiani). It was found that the maximum daily growth rates for green and red strains of K.
alvarezii cultivated in Jambiani were 7.3% and 6.5% respectively, recorded September and July during
Southeast SE monsoon. Lowest growth rates for green and red strains of K. alvarezii grown in Jambiani were
_3.1% and _1.8% observed in January and March during Northeast NE monsoon. The highest growth rate for
the green strain of K. alvarezii was measured at a time when seawater temperature was lower than 240C,
salinity was 35.5‰ and underwater light intensity was 2866 mol photon.m _2.s_1 and for the red strain,
seawater temperature was 25.60C, salinity was 34.5 ‰ and underwater light intensity was 1685 mol
photon.m _2.s_1. The lowest growth rate for the green strain of K. alvarezii was recorded during the time of the
year when seawater temperature was 33.90C, salinity was 36‰ and underwater light intensity was 2990 mol
photon.m _2.s_1 and for the red strain, seawater temperature was 32.60C, salinity was 36‰ and underwater
light intensity was 2770 mol photon.m _2.s_1. The environmental conditions such as high seawater
temperature, salinity, and underwater light intensity, and salinity observed during the NE monsoon period,
might be contributed to lower growth rates. The NE monsoon is associated with calm seas that caused warm
water an increase in water temperature and no water circulation.
TEMPORAL AND SPATIAL VARIATION IN MICROPHYTOBENTHIC BIOMASS IN RELATION TO
CHANGES IN PHYSICO_CHEMICAL CHARACTERISTICS OF A SMALL TEMPORARILY OPEN_CLOSED
ESTUARY IN THE EASTERN CAPE (oral)
Tracy Skinner, P. T. Gama and J. B. Adams
Department of Botany, University of Port Elizabeth
[email protected]
During the period March_December 2003 studies were conducted on a quarterly basis on the effects of
physico_chemical conditions on microphytobenthic biomass in a small temporarily open_closed estuary. The
Van Stadens estuary, situated 30km west of Port Elizabeth, was sampled for physico_chemical characteristics,
sediment type and pore_water nutrients. Microphytobenthic biomass, as chlorophyll a, was measured at three
sites along the estuary, corresponding to the low, mid and upper reaches of the estuary. The mouth of the
estuary remained closed for most of the year except for approximately 4_5 days in October when it opened
allowing saline water intrusion into the estuary. Water temperature in the estuary followed a typical warm
temperate seasonal trend with cool and warm waters in winter and summer respectively. A slight vertical and
horizontal halocline developed during the months of March, June and September, while during December the
estuary was well mixed. The sediment type in the estuary was predominantly made up of sand (125_500m),
however from March_September coarse sediment (>500m) was co_dominant and during December mud
(63_125m) was co_dominant particularly in the mid_upper reaches. Sediment organic content was generally
found to increase from the lower to the upper reaches of the estuary. Pore_water and water column nutrient
concentrations were spatially and temporally variable with no clear trends throughout the sampling period,
although pore_water concentrations were generally higher than water column concentrations. In March,
microphytobenthic biomass was significantly higher than from June_December, there was, however, no
significant difference in biomass between the sites sampled. Slight differences found between sites appear to
be linked to sediment organic content and pore_water nutrient concentrations. Temporal variation in benthic
biomass is explained by the difference in salinity rather than temperature, indicating that the
microphytobenthos is greatly influenced by fresh_ and saltwater interactions within the Van Stadens estuary.
THE CURRENT STATE OF SEAWEED NATURAL PRODUCTS (BIOACTIVE COMPOUNDS) IN DRUG
DISCOVERY (oral)
AJ Smit
Botany Department, University of Cape Town
[email protected]
Seaweeds have been used as sea vegetables, herbal medicines, cattle fodder and fertiliser in Asia_Pacific,
European and Mediterranean regions for centuries. In the last century, natural hydrocolloids from macroalgae
have revolutionised industrial processes such as the manufacturing of processed foods, and their gelling
properties have been exploited in many research fields. A much younger aspect of seaweed product utilisation
is that of looking towards their bioactive substances as lead agents in medical and pharmaceutical product
development. In the last three decades the discovery of interesting metabolites with unique biological activities
from seaweeds has increased dramatically, but despite the intense research effort by academic and corporate
institutions, very few products with real potential have been identified or developed. Algal products that
currently receive most attention by pharmaceutical companies include the sulphated polysaccharides as
antiviral (including anti_HIV) substances, halogenated furanones from Delisea pulchra as antifouling
compounds, and kahalalide F from a species of Bryopsis as a possible treatment of lung cancer, tumours and
AIDS. Various other substances such as algal lectins, fucoidans, kainoids and aplysiatoxins are routinely used
in biomedical research, and a multitude of other substances have known biological activities.
PHYSICO_ CHEMICAL FACTORS DETERMINING BENTHIC MICROALGAL DISTRIBUTION IN OPEN
SOUTH AFRICAN ESTUARIES (oral)
Gavin C. Snow and J. B. Adams
Department of Botany, University of Port Elizabeth
[email protected]
Six permanently open estuaries along the southeastern coast of South Africa were sampled for intertidal
benthic chlorophyll a, water quality (salinity, total oxidised nitrogen (TOxN), soluble reactive phosphate,
ammonium and silicate) and sediment composition (organic content, % moisture and sediment size fractions).
Chlorophyll a ranged from 0 to 105 g g_1 in the estuaries and was significantly higher in samples collected in
winter than those collected in summer, which is probably the result of significantly higher concentrations of
TOxN occurring in winter samples. Intertidal benthic chlorophyll a was most strongly associated to the organic
content, moisture content and the fraction of very fine grains (<125 m) in the sediment. Water quality of the
overlying water was only weakly associated with chlorophyll a, with TOxN the only positively correlated
nutrient. The results of the study indicate that sediment composition was the most important factor determining
benthic chlorophyll a distribution and overlying water quality only became a strong determining factor at sites
where organic content and the fraction of fine grain sediments was low.
CULTIVATING Gelidium pristoides IN A SPRAY CULTIVATION SYSTEM (poster)
Paul_Pierre Steyn and D. R. du Preez
Botany Department, University of Port Elizabeth
[email protected]
Previously unsuccessful attempts at growing Gelidium pristoides (Turner) Kützing, a rocky shore intertidal
rhodophyte, in traditional tank culture systems have led to an investigation into the alga's response to various
physical conditions. Based on these, the optimum culture environment for the species has been established.
Substantially elevated photosynthetic rates were measured when photosynthesis was measured in exposed
samples after some dehydration (0.01 mol O2 g_1 s_1 to 0.017 mol O2 g_1 s_1, a 70 % increase). This
prompted growth trials using a spray cultivation system in a controlled environment. Two spray regimes were
tested. One maintaining the algae at the optimum hydration state for maximum photosynthesis (80% relative
moisture content); and a spray regime most closely resembling the tidal environment, in which the alga grows
naturally (varying spray frequency, light intensity and temperature). The algae responded negatively to both
treatments by a lowering in growth, bleaching and becoming necrotic (_0.37 ± 1.7 % week_1 and _0.57 ± 0.9%
week_1 respectively). Possible bacterial infection under sub_optimal growth conditions may be responsible for
algal degradation.
POTENTIAL BENEFITS OF USING MICROALGAE (CHLOROPHYTA) AS SOIL ADDITIVES FOR
AGRICULTURAL APPLICATION (oral)
Wendy A. Stirk1, V. Ördög2, O. Novák3, M. Strnad3, J. van Staden1, J. Szigeti4 and L. Németh5
1
Research Centre for Plant Growth and Development, University of Natal Pietermaritzburg
2
Department of Plant Physiology and Plant Biotechnology, Faculty of Agricultural and Food Science,
University of West Hungary, Hungary
3
Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany AS CR, Czech
Republic
4
Institute of Food Science, Faculty of Agriculture and Food Science, University of West Hungary, Hungary
5
Department of Plant Protection, Faculty of Agricultural and Food Science, University of West Hungary,
Hungary
[email protected]
One hundred and ninety eight axenic microalgal strains (Cyanophyta and Chlorophyta) were screened for
inhibitory activity against some bacteria, filamentous fungi and yeasts using a disc_diffusion type bioassay.
From this initial screening, ten strains from three Chlorophyta genera (Protococcus, Chlorella and
Scenedesmus) were selected due to their high inhibitory activity. These ten strains were further tested using a
MIC antimicrobial assay. These preselected microalgal strains showed a high incidence of antibacterial activity
against both Gram_positive (nine out of ten species) and Gram_negative (seven out of ten species) bacteria.
The same strains were also analysed for endogenous cytokinins. Ethanolic extracts of the microalgae
containing a mixture of deuterium labelled standards were purified using a combined DEAE_Sephadex
octadecylsilica column and IAC based on wide_range specific monoclonal antibodies and analysed by HPLC
linked to a Micromass single quadrupole mass spectrometer with an electrospray interface and a photodiode
array detector. There were similar trends in cytokinin profiles for the nine microalgal strains investigated
although concentrations did vary. Both iP and iPR were detected in all nine strains. cZ and cZR occurred at
higher concentrations than the trans isomers while tZOG and tZROG were dominant over the cis isomers.
DHZ and its conjugates were not detected in any significant amounts. The aromatic BA always occurred at
higher concentrations than BAR. The topolins were well represented with all three isomers (ortho, meta and
para) being detected with oT and oTR occurring at higher concentrations than the other isomers. However, for
the O_glucosides, the meta isomers (mTOG and mTROG) occurred at higher concentrations than the other
isomers. No N_glucosides were detected (iP9G, Z9G, DHZ9G, BA9G, oT9G and mT9G). Generally, zeatin
and topolin conjugates were the dominant forms of isoprenoid and aromatic cytokinins respectively. There was
no distinct trend in the proportions of isoprenoid to aromatic cytokinins.
ON THE IDENTITY OF A BLOOM_FORMING Tetraselmis SPECIES FROM SALDANHA BAY (oral)
1
Stuart D. Sym1, F. Khosa1, C. Marangoni1 and G. C. Pitcher2
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
2
Marine & Coastal Management, Cape Town
[email protected]
In January 2003, Saldanha Bay was affected by a massive, but harmless bloom of Tetraselmis. Isolated cells
were cultured and were subjected to routine light and transmission electron microscopy in an attempt to
identify the organism. Several features of this organism are important for identification: 1. This specimen has
a multi_layered theca which, when shed, rolls up in a scroll_like fashion. 2. The theca lacks fine hairs that
cover the thecal surface. 3. There are no hairs in the flagellar pit area. 4. They have Type 3a and 3b hair
scales on the flagella. 5. The pyrenoid is invaded, from the anterior only, by cytoplasmic fingers which do not
include any extension of the nucleus. The taxonomy of Tetraselmis is confusing at present and is in desperate
need of revision. The hair scale type exhibited by this organism is found in T. verrucosa (Type 3a) and T.
marina (Type 3b), both of which are species of the subgenus Prasinocladia. However, members of this
subgenus are typified by having their pyrenoid invaded from the anterior side by lobes of the nucleus, and the
state of this character in the Saldanha Bay material points to it belonging to the subgenus Tetrathele. Clearly,
these characters are in conflict and the phylogenetics of the genus needs molecular clarification.
A SANDY BEACH ECOSYSTEM HEALTH INDEX AND EXPERT SYSTEM OR BEACH MANAGEMENT IN
THE EASTERN CAPE (poster)
W. B. Todkill, D. R. du Preez and E. E. Campbell
Botany Department, University of Port Elizabeth
[email protected]
Descriptive research has been conducted on large sandy beach ecosystems in the Eastern Cape and
management principles developed. Based on studies of primary producers of sandy beaches around the
whole South African coast, it is clear that there are at least five different types of sandy beach ecosystems and
that each of these has different ecosystem functioning. The criteria for determining ecosystem health for beach
health are likely to be different for each type. The major research question relates to the developing of an
ecosystem health index for the different sandy beach types of the Eastern Cape. This index will be applied to
the Eastern Cape beaches, which will then be classified according to their use by people, ecosystem
functioning and health. The conservation priority of each beach can then be assessed. In previous studies,
emphasis has been placed on large sandy beaches that are likely to be affected by tourism pressures. The
beaches of, for example, the Wild Coast have, largely not been studied. This project aims to fill this gap in our
knowledge of sandy beach functioning. It is clear that an integrated management program should be
developed for Eastern Cape beaches _ one that will indicate which beaches are "important" from a utilisation,
conservation and ecosystem health perspective. This program will provide managers with the tools they
require for decision_making. An Expert System has been used to this end in estuarine management and the
same approach could be used for sandy beaches managers.
THE DIVERSITY AND DISTRIBUTION OF Ptilophora (GELIDIACEAE, RHODOPHYTA) INCLUDING TWO
NEW SPECIES FROM KWAZULU_NATAL (oral)
Enrico M Tronchin1, J.J. Bolton1 and R.J. Anderson2
1
2
Botany Department, University of Cape Town
Seaweed Unit, Marine and Coastal Management
[email protected]
The genus Ptilophora consists of large (ca. 30 cm long), frondose algae belonging to the Gelidiaceae, a family
of economically important red seaweeds. These plants are characterised by a four_layered vegetative
structure with large, elliptical inner cortical cells in transverse sectional view, and a distichously branched frond
that usually bears a midrib. The genus occurs in deep subtidal habitats and is rarely encountered as a
consequence. It occurs predominantly in temperate waters and has an Indian Ocean and West Pacific
distribution. The genus is well represented in South Africa where eight of the sixteen currently accepted
species occur, distributed along the KwaZulu Natal and northern Eastern Cape coast (with six species
endemic to this region). Based on morphological observations and phylogenetic analyses of rbcL and LSU
gene sequences, two new species (Ptilophora coppejansii and Ptilophora leliaertii) are described from Protea
Banks reef (KwaZulu_Natal), and Ptilophora helenae from South Africa is resurrected after having been placed
in synonymy with Ptilophora pectinata from Australia (Norris, 1992).
THE BLACK SEA PHYTOPLANKTON SEEN THROUGH AN "ENVIRONMENTAL WINDOW" (oral)
Violeta N. Velikova
School of Animal, Plant & Environmental Sciences, University of the Witwatersrand
[email protected]
The Black Sea has been nominated many times as one of the most "unique" basins on Earth for many reasons
_ complicated geological past, sharp hydrophysical gradients, mean residence time up to about 2000 years,
worst environmental degradation, best ground_truth data for validation of SeaWIFS images and the last but
not least _ long_term history of chronic harmful algal blooms. The phytoplankton variability, frequency and
amplitude of blooms, changes in species composition are well documented in bibliography and during the last
30 years mainly related to man_induced negative alterations of the environment. In the early 1990_s the basic
sources of the Black Sea degradation were listed in the following order: eutrophication, overfishing,
introduction of exotic species as Mnemiopsis, regulation of the Danube river inflow.
Undoubtedly the listed human activities have caused significant changes along the chain of trophic relations in
the Black Sea. Eutrophication, for example, classically enhanced the primary production, increased the
frequency of algal blooms, changed the list of predominating species (mentioned persistently in bibliography:
from diatoms to dinoflagellates). The depression of silicates in the Black Sea was also supposed to have a
subsequent effect on the diatom algae. The establishment of this relationship was considered to be very
important since previously the decline in the biomass of these algae had only been related to solar activity
variations. Overfishing of large predators caused trophic cascade in the Black Sea. Mass development of
small pelagic fish (consuming food zooplankton), outbreaks of Mnemiopsis and Noctiluca (consuming
zooplankton eggs) marked significant changes in the production system of the sea. All these resulted in
depression of zooplankton, upset the grazing control and contributed additionally to algal blooms.
However, in the middle and late 1990_s the endless debates about the irreversible "green death" of the Black
Sea came to a point of flexibility. The routine monitoring of the Sea revealed numerous positive changes in the
ecosystem. Undoubtedly, the end (or pause) of the environmental crisis was first related to the decreased
nutrient input into the Sea. There appeared publications that the 1990_s phytoplankton was more close to
natural fluctuations, reflecting climatic influence on the background of a reduced anthropogenic impact.
However, the period of restoration of the water quality in the Black Sea seems too short after the long_term
man_made alterations of the ecosystem. Obviously, during the period of "progressive eutrophication" (1970_s
and 1980_s) not only the human activities have been contributing to the increase in phytoplankton blooms.
The "environmental window" in the analysis of the algal dynamics should have always been a complex of
natural and anthropogenic factors. This paper will reveal some climatic _ hydrological factors, which control
the phytoplankton community and outline the pattern of natural processes as a basis for overlapping human
influence.
LIST OF ATTENDING DELEGATES
Anderson, Robert J. _ Seaweed Unit, Marine and Coastal Management, Pvt Bag X2, Roggebaaai, 8012
([email protected])
Bolton, John J. _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Buchanan, Sean _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand,
Private Bag 3, WITS 2050 ([email protected])
Campbell, Eileen E. _ Botany Department, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Clark, Belinda J. _ Botany Department, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Difford, Mark _ Botany Department, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Dotto, Salum M. _ Institute of Marine Sciences, P. O. Box 668, Zanzibar, Tanzania
[email protected] (or) [email protected]
Dukhan, Shalini _ School of Animal, Plant and Environmental Sciences, University of the Witwatersrand,
Private Bag 3, WITS 2050 ([email protected])
Du Preez, Derek R. _ Botany department, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Evans, Adrian G. _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Griffin, Neil J. _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Kirton, Alecia _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand, Private
Bag 3, WITS 2050 ([email protected])
Leitao, Daniela _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Maneveldt, Gavin W. _ Department of Biodiversity and Conservation Biology, University of the Western Cape,
P. Bag X17, Bellville, 7535 ([email protected])
Marangoni, Claudio _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand,
Private Bag 3, WITS 2050 ([email protected])
Mason, Richard M. _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand,
Private Bag 3, WITS 2050 ([email protected])
Naidoo, Krishni _ Department of Biodiversity and Conservation Biology, University of the Western Cape, P.
Bag X17, Bellville, 7535 ([email protected])
Pitcher, Grant C. _ Marine and Coastal Management, Private Bay X2, Rogge Bay, 8012
([email protected])
Rand, Andrew M. _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Robertson_Andersson, Deborah V. _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Rothman, Mark D. _ Seaweed Unit, Marine and Coastal Management, Pvt Bag X2, Roggebaaai, 8012
([email protected])
Rotmann, Klaus W. G. - Taurus Products, PO Box 5534, Rivonia, 2128 (krotmann@taurus_products.co.za)
Ruscoe, Wendy - Taurus Products, PO Box 5534, Rivonia, 2128 (wruscoe@taurus_products.co.za)
Skinner, Tracy _ Department of Botany, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Smit, AJ _ Botany Department, University of Cape Town, Rondebosch, 7701
([email protected])
Smith, Andy C. _ Department of Botany, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Snow, Gavin C. _ Department of Botany, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Steyn, Paul_Pierre _ Department of Botany, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Stirk, Wendy A. _ Research Centre for Plant Growth and Development, University of Natal Pietermaritzburg,
P/Bag X01, Scottsville 3209 ([email protected])
Sym, Stuart D. _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand, Private
Bag 3, WITS 2050 ([email protected])
Todkill, W. B. _ Botany Department, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000
([email protected])
Tye, Nicholas - School of Animal, Plant & Environmental Sciences, University of the Witwatersrand, Private
Bag 3, WITS 2050
Velikova, Violeta N. _ School of Animal, Plant & Environmental Sciences, University of the Witwatersrand,
Private Bag 3, WITS 2050 ([email protected])